FIG. 1 schematically illustrates a prior-art packaging arrangement 10 for a high-power CO2 slab-laser system 10. The arrangement includes three basic subsystems packaged in separate enclosures. The three subsystems are a solid-state high-power RF power supply (RFPS) in enclosure 12; an RF impedance-matching network in enclosure 14 including components required to match the output impedance of the RFPS to the input impedance of the laser-discharge; and a hermetically sealed CO2 laser tube housing 16 that contains laser-discharge electrodes in a lasing-gas mixture and an optical resonator. A fourth subsystem containing optical components for modifying the output laser-beam is not shown in FIG. 1. This fourth subsystem includes a spatial-filter assembly for cleaning-up the laser beam, and lenses for shaping the laser beam; an optical detector for informing the user if a laser beam is being emitted; and an electronically controlled safety-shutter to protect the user from accidental laser radiation exposure.
In order to prevent stray RF radiation from causing electromagnetic (EM) interference, all three sub-assembly enclosures are typically grounded metal enclosures, and input and output ports of the enclosures are all heavily shielded. In order to prevent overheating at high-power laser operation, for example, operation at above 250 W of laser-output power, all three enclosures and the optical subsystem are provided with liquid cooling, as indicated schematically in FIG. 1.
DC power input 18, typically at 48 volts, is provided to the RFPS 12 An input-command signal port 20 is also provided to enable a system operator to provide turn-on and turn-off pulsing instructions to the RFPS, and also to provide open and close commands to the safety-shutter (not shown). RFPS 12 may also contain diagnostic circuitry for reporting the status of laser system 10, via line 22, to an operator.
From consideration of efficiency, size, and cost of the laser system, it is desirable to locate enclosures 12, 14, and 16, and the above discussed optical subassembly, as close together as possible. This serves to reduce RF and optical losses, in addition to reducing costs associated with providing interconnecting co-axial cables. This of course does not reduce basic cost and effort of building, cooling, and interconnecting the separate enclosures.
Some details of internal arrangements of enclosures 12, 14, and 16, and interconnections therebetween, are schematically depicted in FIG. 2. In RFPS enclosure 12 only an arrangement for combining the outputs of multiple amplifier stages via a plurality of coaxial cable sections 24 is depicted for simplicity of illustration. Such a power combining arrangement is described in U.S. Pat. No. 7,755,452 assigned to the assignee of the present invention, and the complete disclosure of which is hereby incorporated herein by reference.
The combined single output of the RFPS is passed through a well-shielded RF-interconnect box 26 to bring the combined power from the RFPS to an impedance-matching network 28, here, comprising inductances L1 and L2, and capacitors C1 and C2. Inductances L1, L2, and capacitor C1 are connected together at a common node 29. The output of impedance-matching network 28 connects to a hermetically sealed, low-impedance feed-through in enclosure 16, indicated by dashed outline 30, to match the impedance ZL of discharge-electrodes 34 and 36 of the laser.
Laser systems such as system 10 are typically integrated into much larger apparatus for carrying out some laser-process such as laser-machining, or laser heat-treatment. Because of this, there is always a demand for reducing the size and complexity of such a laser-system to make the laser-system more easily integrated into the laser-processing system and to make the processing system itself more compact.